Hoist

ABSTRACT

The purpose of the present invention is to provide a hoist that has a simple configuration while being capable of withstanding heavy loads. Accordingly, the hoist ( 1 ) is provided with: a sheave ( 10 ); a left stand ( 11 ) and a right stand ( 12 ) that rotatably support the sheave ( 10 ) at both ends in the axial direction; a rotor ( 4 ) installed on the end of the sheave ( 10 ) on the left stand ( 11 ) side; a stator ( 5 ) installed at a position facing the inner diameter side of the rotor ( 4 ); a brake disc ( 30 ) installed on the same axis as the sheave ( 10 ) on the end of the sheave ( 10 ) on the right stand ( 12 ) side; and a brake device ( 31 ) that is installed on the right stand ( 12 ), and that applies pressure to the brake disc ( 30 ) to provide braking.

TECHNICAL FIELD

The present invention relates to a hoist.

BACKGROUND ART

A hoist for use in an elevator and the like is conventionally known. Forexample, in a conventional hoist disclosed in Patent Document 1 below, arotor is supported by a cantilever shaft, and when a sheave is put undera load, the cantilever shaft is curved. This makes the air-gap of themotor uneven and thus lowers the motor performance. Further, in aworst-case scenario, friction might occur in the air gap, makingimpossible for the motor to operate.

Accordingly, in the conventional hoist, the curving of the cantilevershaft caused by a load has to be reduced. In one method of reducing thecurving of the cantilever shaft caused by a load, the diameter of thecantilever shaft is increased to reduce the curving.

PRIOR ART DOCUMENT Patent Document

Patent Document 1: Japanese Patent Application Publication No. Hei9-142761

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

The conventional hoist described above employs the method of increasingthe diameter of the cantilever shaft to reduce the curving caused by aload.

However, in an extremely large hoist, the diameter of the cantilevershaft needs to be increased so much that it is difficult to adopt thismethod.

Moreover, when the cantilever shaft is large, a bearing and a framesupporting the cantilever shaft also have to be large. Consequently, thehoist becomes very large and heavy.

In addition to the above problem, such a hoist has a problem ofrequiring high costs.

In consideration of the above, the present invention has an objective ofproviding a hoist having a simple configuration yet capable ofsupporting a heavy load.

Means for Solving the Problems

To solve the above problems, a hoist according to a first invention ischaracterized in that the hoist comprises: a sheave; first supportingmeans and second supporting means for supporting the sheave at both endsof the sheave in an axial direction thereof, respectively, such that thesheave is rotatable; a rotor placed on the end portion of the sheave onthe first supporting means side; a stator placed at a position facing aninner side of the rotor; a brake disk placed on the end portion of thesheave on the second supporting means side coaxially with the sheave;and braking means for providing braking by applying a pressure to thebrake disk, the braking means being placed on the second supportingmeans.

To solve the above problems, a hoist according to a second invention isthe hoist according to the first invention and is characterized in thatthe hoist further comprises, between the first supporting means and thesecond supporting means, maintaining means for maintaining a gap betweenthe first supporting means and the second supporting means.

To solve the above problems, a hoist according to a third invention isthe hoist according to the first invention or the second invention andis characterized in that the hoist further comprises: a rotationdetection shaft placed at an axial end of the sheave and penetrating thefirst supporting means; and rotation detecting means placed on therotation detection shaft.

Effect of the Invention

The present invention can provide a hoist having a simple configurationyet capable of supporting a heavy load.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a hoist according to a first embodiment ofthe present invention.

FIG. 2 is a side view of the hoist according to the first embodiment ofthe present invention.

FIG. 3 is a front view of the hoist according to the first embodiment ofthe present invention.

FIG. 4 is a rear view of the hoist according to the first embodiment ofthe present invention.

FIG. 5 is a sectional view of another example of the hoist according tothe first embodiment of the present invention.

FIG. 6 is a sectional view of a hoist according to a second embodimentof the present invention.

FIG. 7 is a side view of the hoist according to the second embodiment ofthe present invention.

FIG. 8 is a front view of the hoist according to the second embodimentof the present invention.

FIG. 9 is a rear view of the hoist according to the second embodiment ofthe present invention.

FIG. 10 is a sectional view of another example of the hoist according tothe second embodiment of the present invention.

FIG. 11 is a sectional view of a hoist according to a third embodimentof the present invention.

FIG. 12 is a side view of the hoist according to the third embodiment ofthe present invention.

FIG. 13 is a front view of the hoist according to the third embodimentof the present invention.

FIG. 14 is a rear view of the hoist according to the third embodiment ofthe present invention.

FIG. 15 is a sectional view of another example of the hoist according tothe third embodiment of the present invention.

MODES FOR CARRYING OUT THE INVENTION

With reference to the drawings, a description is given below of modesfor carrying out a hoist according to the present invention.

Embodiment 1

A first embodiment of the hoist according to the present invention isdescribed below.

First, the configuration of the hoist according to this embodiment isdescribed.

FIG. 1 is a sectional view of the hoist according to this embodiment.FIG. 2 is a side view of the hoist according to this embodiment. FIG. 3is a front view of the hoist according to this embodiment. FIG. 4 is arear view of the hoist according to this embodiment. FIG. 5 is asectional view of another example of the hoist according to thisembodiment. Note that the “left” and “right” in the followingdescription are based on the left and right in FIGS. 1, 2, and 5.

As shown in FIGS. 1 to 4, in a hoist 1 according to this embodiment, asheave 10 has a structure in which an outer cylinder 10 a and an innercylinder 10 b are joined to each other with a connecting portion 10 c.In a left stand 11A, a support portion 11 a is formed to place thesheave 10 horizontally. In a right stand 12, a support portion 12 a isformed to plate the sheave 10 horizontally.

A left bearing 13 is placed between the inner cylinder 10 b of thesheave 10 and the support portion 11 a of the left stand 11 and supportsthe sheave 10 such that the sheave 10 is rotatable. A right bearing 14is placed between the inner cylinder 10 b of the sheave 10 and thesupport portion 12 a of the right stand 12 and supports the sheave 10such that the sheave 10 is rotatable.

An outer race 13 a of the left bearing 13 and an outer race 14 a of theright bearing 14 are joined to an inner side of the inner cylinder 10 bof the sheave 10. An inner race 13 b of the left bearing 13 is joined toan outer side of the support portion 11 a of the left stand 11. An innerrace 14 b of the right bearing 14 is joined to an outer side of thesupport portion 12 a of the right stand 12.

The sheave 10 is placed between the left stand 11 and the right stand 12as follows. First, the left stand 11 and the right stand 12 aretemporarily secured to a bed 15. Then, the sheave 10 is placed betweenthe left stand 11 and the right stand 12, and the distance andmisalignment between the left stand 11 and the right stand 12 arecorrected so as to center a rotation axis of the sheave 10. Last, theleft stand 11 and the right stand 12 are secured to the bed 15.

A rotor core 20 is placed on an end portion of the sheave 10 on the leftstand 11 side, and a magnet 21 is placed on an inner side of the rotorcore 20. The rotor core 20 and the magnet 21 constitute a rotor 4, orthe secondary, of a motor. A stator core 22 is placed in the left stand11 at a position facing the magnet 21, and a field winding 23 is placedin the stator core 22. The stator core 22 and the field winding 23constitute a stator 5, or the primary, of the motor. Then, the rotor 4and the stator 5 constitute a motor part 2.

The rotor core 20 is configured as a separate member from the sheave 10in this embodiment, but may be formed integrally with the sheave 10 asshown in FIG. 5.

A disk-shaped brake disk 30 is placed on an end portion of the sheave 10on the right stand 12 side. In the right stand 12, a brake device 31configured to brake rotation of the sheave 10 is placed. In FIGS. 1 and5, the brake device 31 is shown with two-dot chain lines.

The brake device 31 includes friction portions 32, such as linings,which face the brake disk 30 and sandwich the brake disk 30therebetween. The brake device 31 can stop the rotation of the sheave 10by sandwiching the brake disk 30 with its friction portions 32. Thebrake disk 30 and the brake device 31 configure a brake part 3.

The brake disk 30 is configured as a separate member from the sheave 10in this embodiment, but may be formed integrally with the sheave 10 asshown in FIG. 5.

Although a disk braking method is employed in this embodiment, othermethods can be employed, such as a drum braking method for instance.

The motor part 2 and the brake part 3 are placed on the left side and onthe right side, respectively, in this embodiment, but may be placed onthe right side and on the left side, respectively, instead.

Above is the description of the configuration of the hoist 1 accordingto this embodiment.

Next, the operation of the hoist 1 according to this embodiment isdescribed.

In the hoist 1 according to this embodiment, the sheave 10 is rotatablysupported by the left stand 11 and the right stand 12. The left stand 11and the right stand 12 are secured after the rotation axis of the sheave10 is centered.

The rotor 4 rotates when the motor part 2 is driven with the frictionportions 32 of the brake device 31 being out of contact with the brakedisk 30, namely, in a brake opening state. Since the rotor 4 is joinedto the sheave 10 which is joined to the brake disk 30, the rotor 4, thesheave 10, and the brake disk 30 rotate together. Accordingly, therotation of the sheave 10 and the brake disk 30 can be controlled bycontrolling the rotation of the motor part 2.

Then, when pressure is applied by pushing the friction portions 32 ofthe brake device 31 against the brake disk 30, namely in a brakeoperating state, a brake torque is generated in the brake disk 30, andthe rotating brake disk 30 slows down and stops. After stopping, thebrake disk 30 keeps its stopped state.

When the brake is actuated after the brake disk 30 is stopped by controlof the speed of the motor part 2, the brake disk 30 can keep its stoppedstate, as well. Then, since the rotor 4, the sheave 10, and the brakedisk 30 are integral with each other, they can be rotated and stoppedtogether.

Above is the description of the operation of the hoist 1 according tothis embodiment.

As described above, the hoist 1 according to this embodiment isconfigured such that the rotor 4 and the brake disk 30 are directlyattached to the sheave 10. Accordingly, a cantilever shaft isunnecessary, which can simplify the structure of the hoist 1.

Moreover, since the cantilever shaft which can be easily curved isunnecessary, the hoist 1 according to this embodiment is free from theproblem of the curving of the cantilever shaft caused by a load on theshaft. In addition, using fewer components than the conventional hoist,the hoist 1 according to this embodiment can be reduced in size andweight.

Further, since the cantilever shaft which can be easily curved isunnecessary to make the hoist 1 according to this embodiment free fromthe problem of the curving of the cantilever shaft caused by a load onthe shaft, a super large hoist can be manufactured.

In addition, since the hoist 1 according to this embodiment has a simplestructure to be able to reduce its size and weight, cost reduction canbe achieved.

Moreover, since the hoist 1 according to this embodiment can be reducedin size, space for installing an elevator can be reduced.

Thus, the hoist 1 according to this embodiment can provide a hoisthaving a simple configuration yet capable of supporting a heavy load.

Embodiment 2

A second embodiment of the hoist according to the present invention isdescribed below.

FIG. 6 is a sectional view of the hoist according to this embodiment.FIG. 7 is a side view of the hoist according to this embodiment. FIG. 8is a front view of the hoist according to this embodiment. FIG. 9 is arear view of the hoist according to this embodiment. FIG. 10 is asectional view of another example of the hoist of this embodiment. Notethat the “left” and “right” in the following description are based onthe left and right in FIGS. 6, 7, and 10.

As shown in FIGS. 6 to 9, the configuration of the hoist 1 according tothis embodiment is almost the same as that of the hoist 1 according tothe first embodiment, but is different from it in includingupper-portion maintaining members 40 and lower-portion maintainingmembers 41. The upper-portion maintaining members 40 are placed betweenan upper portion of the left stand 11 and an upper portion of the rightstand 12 to maintain the gap between the left stand 11 and the rightstand 12, and the lower-portion maintaining members 41 are placedbetween a lower portion of the left stand 11 and a lower portion of theright stand 12 to maintain the gap between the left stand 11 and theright stand 12.

Each upper-portion maintaining member 40 is secured to the left stand 11by a nut 40 a, and to the right stand 12 by a nut 40 b. Eachlower-portion maintaining member 41 is secured to the left stand 11 by anut 41 a, and to the right stand 12 by a nut 41 b.

Accordingly, in the hoist 1 according to this embodiment, when the hoist1 is assembled, the gap between the left stand 11 and the right stand 12is automatically determined by the upper-portion maintaining members 40and the lower-portion maintaining members 41 which are additionallyprovided. Accordingly, the centering of the rotation axis of the sheave10 can be omitted.

The rotor core 20 is configured as a separate member from the sheave 10in this embodiment, but may be formed integrally with the sheave 10 asshown in FIG. 10.

In addition, the brake disk 30 is configured as a separate member fromthe sheave 10 in this embodiment, but may be formed integrally with thesheave 10 as shown in FIG. 10.

As described above, in addition to the effects offered by the hoistaccording to the first embodiment, the hoist 1 according to thisembodiment allows omission of the troublesome work of centering therotation axis of the sheave 10 because the rotation axis of the sheave10 can be centered automatically at the time of assembly of the hoist 1.

Embodiment 3

A third embodiment of the hoist according to the present invention isdescribed below.

FIG. 11 is a sectional view of the hoist according to this embodiment.FIG. 12 is a side view of the hoist according to this embodiment. FIG.13 is a front view of the hoist according to this embodiment. FIG. 14 isa rear view of the hoist according to this embodiment. FIG. 15 is asectional view of another example of the hoist according to thisembodiment. Note that the “left” and “right” in the followingdescription are based on the left and right in FIGS. 11, 12, and 15.

As shown in FIGS. 11 to 14, the configuration of the hoist 1 accordingto this embodiment is almost the same as that of the hoist 1 accordingto the first embodiment, but is different from it in having a raisedportion 10 d on the inner side of the inner cylinder 10 b of the sheave10 and in including a rotation detection shaft 50 placed on this raisedportion 10 d and a rotation detector 60 placed on the rotation detectionshaft 50.

The rotation detector 60 is configured by an inner rotary part 60 a andan outer stationary part 60 b. The rotary part 60 a of the rotationdetector 60 is fixed to the rotation detection shaft 50 by a nut 50 a.The stationary part 60 b of the rotation detector 60 is fixed to theleft stand 11 by a fixing member 11 b.

Accordingly, in the hoist 1 according to this embodiment, the rotationdetection shaft 50 placed on the raised portion 10 d of the inner sideof the inner cylinder 10 b of the sheave 10 rotates along with thesheave 10. Then, being attached between the rotation detection shaft 50and the left stand 11, the rotation detector 60 rotates along with thesheave 10 and thus can detect the rotation of the motor part 2 coming toa stop.

The rotor core 20 is configured as a separate member from the sheave 10in this embodiment, but may be formed integrally with the sheave 10 asshown in FIG. 15.

In addition, the brake disk 30 is configured as a separate member fromthe sheave 10 in this embodiment, but may be formed integrally with thesheave 10 as shown in FIG. 15.

Further, although the rotation detector 60 is located on the left inthis example, the rotation detector 60 can instead be located on theright side as shown in FIG. 15. In which case, the stationary portion 60b of the rotation detector 60 is fixed to the right stand 12 by a fixingmember 12 b.

The configuration of the hoist 1 according to this embodiment can alsobe applied to the hoist 1 according to the second embodiment.

As described, in addition to the effects offered by the hoist 1according to the first embodiment, the hoist 1 according to thisembodiment offers the following effect. Specifically, when the hoist 1employs an outer-rotor motor, generally, it is difficult to take out therotation detection shaft 50, and therefore the rotation detector 60 isattached with a complicated structure. However, according to thisembodiment, although the hoist 1 employs an outer-rotor motor, therotation detector 60 can be attached with a simple structure.

INDUSTRIAL APPLICABILITY

For example, the present invention can be applied to a hoist used for anelevator or the like.

EXPLANATION OF REFERENCE NUMERALS

-   1 hoist-   2 motor part-   3 brake part-   4 rotor-   5 stator-   10 sheave-   10 a outer cylinder-   10 b inner cylinder-   10 c connecting portion-   10 d raised portion-   11 left stand-   11 a support portion-   11 b fixing member-   12 right stand-   12 a support portion-   12 b fixing member-   13 left bearing-   13 a outer race-   13 b inner race-   14 right bearing-   14 a outer race-   14 b inner race-   15 bed-   20 rotor core-   21 magnet-   22 stator core-   23 field winding-   30 brake disk-   31 brake device-   32 friction portion-   40 upper-portion maintaining member-   40 a, 40 b nut-   41 lower-portion maintaining member-   41 a, 41 b nut-   50 rotation detection shaft-   50 a nut-   60 rotation detector-   60 a rotary part-   60 b stationary part

1. A hoist characterized in that the hoist comprises: a sheave; firstsupporting means and second supporting means for supporting the sheaveat both ends of the sheave in an axial direction thereof, respectively,such that the sheave is rotatable; a rotor placed on the end portion ofthe sheave on the first supporting means side; a stator placed at aposition facing an inner side of the rotor; a brake disk placed on theend portion of the sheave on the second supporting means side coaxiallywith the sheave; and braking means for providing braking by applying apressure to the brake disk, the braking means being placed on the secondsupporting means.
 2. The hoist according to claim 1, characterized inthat the hoist further comprises, between the first supporting means andthe second supporting means, maintaining means for maintaining a gapbetween the first supporting means and the second supporting means. 3.The hoist according to claim 1, characterized in that the hoist furthercomprises: a rotation detection shaft placed at an axial end of thesheave and penetrating the first supporting means; and rotationdetecting means placed on the rotation detection shaft.